The Prime Minister said he had tried to build on her legacy over his time as Conservative leader, carrying on her reforms.

"I think what we’ve needed to do is take that great inheritance and then add to it, as well as an economic renewal there’s a need for a great social renewal and I think that side of Conservatism needs a boost and that’s what I’ve tried to do over the last seven years."

He said giving power to Britain's regions was one way of improving on Lady Thatcher's era of reform.

"A true Conservative should be following the logic of giving power over their lives," he said.

Mr Cameron later told of the "kindness" Lady Thatcher had shown him as a young researcher in the Conservative Party.

He spoke ahead of Lady Thatcher's funeral at St Paul's Cathedral at 11am. The event will be attended by up to 2,000 guests, including the Queen and former prime ministers.

Around 700 members of the armed forces will be lining the streets, along with crowds of supporters paying their last respects.

Police are expecting protests and have reviewed security arrangements after Monday's Boston bombings.

Some Labour MPs responded indignantly to the idea that everyone is a "Thatcherite now". Mike Gapes, MP for Ilford South, said the idea was "tosh".

Others have criticised the military pomp and expense of the funeral.

However, Mr Cameron insisted it would have looked strange if Britain had not given "a fitting tribute to a great prime minister respected around the world."

He said Ed Miliband, the Labour leader, and Nick Clegg, the Liberal Democrat deputy Prime Minister, were "content" with arrangements for the funeral.

Lord Lawson, a minister under Lady Thatcher, said she had "saved the nation".

The Conservative grandee said his former leader rescued Britain from "economic decline" and "demoralisation".

Speaking before the funeral, Boris Johnson, the London Mayor, said the "astonishing" crowds outside the church showed that people responded to Lady Thatcher's message.

"She spoke to people in a very clear, simple and direct way and she had a very, very powerful message and people responded to it," he told Sky News.